It has taken more than two decades of operations as a private company and two years of detailed investigation, but the Competition Commission has finally concurred with what the vast majority of domestic airlines and millions of air passengers have known for years: BAA's monopoly of the UK's big airports is a very bad idea that has turned flying into a form of torture.

Once, the firm that attracted the most widespread vilification and opprobrium among consumers was Railtrack. Now, without doubt, it is BAA - at least for the 90% of air travellers in the south- east and 84% in Scotland who have little choice but to use its grotty, overcrowded airports if they want to fly.

The commission's report has pointed the finger at BAA for failing to lobby effectively for expansion. Three of its seven airports - probably Gatwick and Stansted, and Glasgow or Edinburgh - will now have to be sold. But at least for several years to come, and for whoever eventually buys the three airports, the watchdog's findings are unlikely to ease the pain of airline passengers.

It could be quite simple and quick to address some of the things that really matter to passengers, such as the interminable queues for check-in and security, the squalid lavatories, the rip-off car parks, gaudy in-your-face shopping malls and departure gates where passengers must sit on the floor.

Big improvements would be possible to all of the above with more resources and different priorities. But the chances of BAA caring about such little things now are almost zero. So we must hope for long-term change instead. The commission acknowledges that it is capacity that is the major factor preventing better service for airlines and passengers. The earliest possible date for a new London runway is 2015 for Stansted. A third runway at Heathrow would not happen for at least 12 years.

The commission reckons a new owner or two might make a rather better fist of what is already available. But that depends on who buys the airports. In a bid to keep out opportunistic investment bank bidders, any buyer will have to have both financial clout and airport management experience.

But that won't mean Goldman Sachs can't sign up a few airport professionals and slap an offer on the table. There will likely be sovereign wealth funds keen to own a trophy asset such as Heathrow and there are certainly infrastructure funds with cash to invest, although the airport owner Macquarie is currently selling rather than buying to cut debt. But the environment has changed markedly in the last year. Aside from tighter credit conditions, there is a more uncertain outlook for the aviation sector and there are likely to be changes to regulation.

In any case, why does the commission think a new debt-funded corporate owner will necessarily be any better than BAA? Many of the best overseas airports against which the London airports compare so unfavourably are state-owned. A new corporate owner will still want to make the best return possible for its shareholders.

And the last time the commission demanded the wholesale sell-off of assets to other operators was the Beer Orders, nearly 20 years ago. They backfired almost completely when the giant breweries, judged over-powerful, were merely replaced by giant pub groups.

The real issue for BAA, as the government's 2003 white paper showed, is that airports and aviation are fast becoming a public policy issue of the highest priority. According to the business lobby, a third runway at Heathrow is the top priority, but the government should not automatically buy that argument just because Sir Nigel Rudd and his CBI chums are banging on about it. They argue that if Heathrow can't expand then Schiphol or Frankfurt will step up and steal our flights.

Well maybe. Or perhaps views other than the impact on big business are now more important. The environmental damage caused by air travel is a far bigger issue than it was when the third runway debate first started. And the price of oil has changed the economics of aviation. It is not a given that London wants another runway and the pollution that goes with it when a third of those arriving at Heathrow are transit passengers who do not contribute to the UK economy.

Arguably airports, like railways, are a vital part of the country's infrastructure. And perhaps, in the same way as Railtrack was reinvented as Network Rail, the airport infrastructure should be operated by a not-for-dividend organisation.

For Ferrovial, the Spanish group that acquired BAA two years ago, it is not a happy outcome. They paid a top dollar enterprise value of £19bn for BAA and are now likely to have to accept fire-sale prices for three airports.

However, they did plough ahead with the bid even after the OFT's initial competition investigation was announced, so it is not as though they did not know what might hit them.